Research to determine optimal delivery methods of respiratory medications that may augment oxygenation by decreasing atelectasis (Lung cell collapse) and increasing oxygen saturation have not been done. Currently bronchodilators are delivered through a passive process, inhaled as they are nebulized (made from liquid into gas) into a face mask. This study will evaluate whether using a newly developed positive pressure nebulization device that uses pressure to expand lung cells and, hypothetically, deliver the medication better, improves oxygenation by reducing atelectasis (lung cell collapse) to decrease hospitalization in infants with moderate to severe bronchiolitis.